Other mistake: At the end of this episode when Jonathan and Nicky set off on horseback to the canal to board the tug boat "Heartsease" they leave late at night and arrive the next day. But in episodes 7 and 8 Margaret rides on horseback to Heartsease and home again, and the journey only takes a few minutes.
Visible crew/equipment: When Nicky picks up the clock you can see the camera lights reflected in the glass.